The formation of dental plaque leads to dental caries, gingival inflammation, periodontal disease, and eventually tooth loss. Dental plaque is a mixture of bacteria, epithelial cells, leukocytes, macrophages, and other oral exudate. Said bacteria produce highly branched polysaccharides which together with micro-organisms from the oral cavity form an adhesive matrix for the continued proliferation of dental plaque.
As dental plaque continues to accumulate rock hard white or yellowish deposits arise. These deposits are called calcified plaque, calculus or tartar, and are formed in the saliva from plaque and minerals, such as in particular calcium.
Oral polysaccharides
Oral polysaccharides mainly consist of the adhesive polysaccharides termed "fructans" and "glucans".
Glucans are produced from carbohydrates, such as sucrose introduced into the mouth, e.g. as a food or beverage constituent, by the action of cariogenic micro-organisms, such as Streptococcus mutans or Streptococcus sanguis, growing in the oral cavity.
The term "glucan" is a general common term covering a number of polysaccharides and includes cellulose, starch, dextran, mutan, pullulan etc.
Oral glucans comprise water-soluble dextran having large portions of a-1,6 glucosidic linkage and as the major component a water-insoluble extra-cellular polysaccharide called "mutan" comprised of a backbone with a-1,3-glycosidic linkages and branches with a-1,6-glycosidic linkages.
Mutan binds to almost any surface such as the surface of teeth, (i.e. hydroxyapatite constituting the hard outer porous layer of the teeth), pellicle, the cell surface of oral micro-organisms as well as to acceptor proteins on the cell of said cariogenic bacteria adhering to the teeth surface.
WO 95/31556 (Unilever) discloses an oral composition comprising the Glucan Binding Domain of glycosyltransferase having specific binding affinity for dextran (being a polysaccharide with mainly .alpha.-1,6-glucosidic linkages).
According to WO 95/31556 the Glucan Binding Domain is covalently chemically bound to material having an activity, such as inhibitory effect against the formation of dental plaque. Said material may be an enzyme, such as galactose oxidase (see Example 6 of said PCT application).
A number of Cellulose Binding Domains are known in the art. Peter Tomme et al., (1996), "Cellulose-Binding Domains: Classification and Properties" in "Enzymatic Degradation of Insoluble Carbohydrates", John N. Saddler and Michael H. Penner (Eds.), ACS Symposium Series, No. 618; Ong et al. (1989), TIBTech 7, p. 239-243; and WO 93/21331 described a vast number of Cellulose Binding Domains.